1. Field of the Invention
This invention relates to a delay line for traveling wave tubes comprising a rectangular wave guide having cross members which extend perpendicularly into the interior of the wave guide. The cross members alternately originate from two inner wall surfaces of the wave guide which face each other.
2. Description of the Prior Art
Delay lines of the type generally described are known in the art in a variety of embodiments. For example, one may refer to the German DAS 1,130,936.
As to the provision of a rectangular shape of a wave guide, reference may be taken to the German DAS 1,243,280.
Delay lines are usually surrounded with radially symmetrically constructed magnets (permanent magnets, coils) in order to produce for the electron beam, which interacts with the following HF wave, a guide field which is as free of cross components as possible. For reasons of a low unit power (required magnetic weight for the development of a certain field of intensity on the axis of the electron beam) the magnet should be positioned as closely as possible to the electron beam. With delay lines having a rectangular form of construction, the smallest possible inner diameter of the magnet is determined by the greatest cross dimension of the line; that is, it is determined by the diagonal through the inside diameter of the line plus a certain amount for the necessary minimum wall thickness of the wave guide.